EXHIBIT 10.20
                         THIRD AMENDMENT
                             OF THE
                     GIANT INDUSTRIES, INC.
                     & AFFILIATED COMPANIES
                           401(K) PLAN
  
  
       WHEREAS, Giant Industries, Inc. and certain of its affiliates
  (the "Employer") adopted the Giant Industries, Inc. & Affiliated
  Companies 401(k) Plan (the "Plan") effective July 1, 1993; and
  
       WHEREAS, the Employer amended and restated the Plan,
  effective July 1, 1993, through an Adoption Agreement dated
  September 10, 1994; and
  
       WHEREAS, the Employer has the authority to amend the Plan.
  
       NOW, THEREFORE, the Employer hereby amends the Plan as
  follows:
  
       Pages 3, 4 and 13, and the Attachment to Adoption Agreement
  for Giant Industries, Inc. & Affiliated Companies 401(k) Plan of
  the existing Plan are hereby removed and replaced by the attached
  replacement pages 3, 4 and 13, and the Attachment to Adoption
  Agreement for Giant Industries, Inc. & Affiliated Companies 401(k)
  Plan.
  
       This amendment is effective July 1, 1998, except as otherwise
  stated in the replacement pages of the attachment.
  
                          GIANT INDUSTRIES, INC. &
                          AFFILIATED COMPANIES
  
  12-10-98                By:  /s/ CHARLES F. YONKER
  --------                   ----------------------------
                          Name: Charles F. Yonker
                          Title: Director Human Resources
  
                          Accepted by:
                          FIDELITY MANAGEMENT TRUST COMPANY,
                          as Trustee
  
  --------                By:----------------------------
                          Name:
                          Title:
  <PAGE>
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       (b)  THE TERM "EMPLOYER" INCLUDES THE FOLLOWING RELATED
            EMPLOYER(S) (as defined in Section 2.01(a)(26)):
  
            See attached sheet.
  
  1.03 COVERAGE
  
       (a)  ALL EMPLOYEES WHO MEET THE CONDITIONS SPECIFIED
            BELOW WILL BE ELIGIBLE TO PARTICIPATE IN THE PLAN.
  
            (1) SERVICE REQUIREMENT (check one):
  
                (A) [ ] no service requirement.
  
                (B) [ ] three consecutive months of service
                        (no minimum number Hours of Service
                        can be required).
  
                (C) [ ] six consecutive months of service (no
                        minimum number Hours of Service can be
                        required).
  
                (D) [X] one Year of Service (1,000 Hours of
                        Service is required during the
                        Eligibility Computation Period.)
  
            (2) AGE REQUIREMENT (check one):
  
                (A) [X] no age requirement.
  
                (B) [ ] must have attached age ___ (not to
                        exceed 21).
  
                                            (Replacement Page,
                                             Third Amendment)
                                3
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  <PAGE>
  (3) THE CLASS OF EMPLOYEES ELIGIBLE TO PARTICIPATE IN THE
      PLAN (check one):
  
      (A) [ ] includes all Employees of the Employer.
  
      (B) [X] includes all Employees of the Employer except
              for (check the appropriate box(es)):
  
              (i)   [X] Employees covered by a collective
                        bargaining agreement.
  
              (ii)  [ ] Highly Compensated Employees as 
                        defined in Code Section 414(g).
  
              (iii) [X] Leased Employees as defined in Section
                        2.01(a)(18).
  
              (iv)  [ ] Nonresident aliens who do not receive
                        any earned income from the Employer
                        which constitutes United States source
                        income.
  
              (v)   [ ] Other
  
           Note: No exclusion in this section may create a
                 discriminatory class of employees. An 
                 Employer's plan must still pass the Internal
                 Revenue Code coverage and participation
                 requirements if one or more of the above
                 groups of Employees have been excluded from
                 the Plan.
  
  (b) THE ENTRY DATE(S) SHALL BE (check one):
  
      (1) [ ] the first day of each Plan Year (not if Section
              1.03 (a)(1)(D) is elected).
  
      (2) [X] the first day of each Plan Year and the date six
              months later. (July 1) See attachment.
  
      (3) [ ] the first day of each Plan Year and the first
              day of the fourth, seventh, and tenth months.
  
      (4) [ ] the first day of each month.
  
                                            (Replacement Page,
                                             Third Amendment)
                               4
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  1.08  PREDECESSOR EMPLOYER SERVICE
  
        [X]  SERVICE FOR PURPOSES OF ELIGIBILITY IN SECTION 1.03(a)(1)
             AND VESTING IN SECTION 1.07(a) OF THIS PLAN SHALL INCLUDE
             SERVICE WITH THE FOLLOWING EMPLOYER(S):
  
        (a)  See attachment.
  
        (b)  See attachment.
  
        (c)  See attachment.
  
        (d)  See attachment.
  
        (e)  See attachment.
  
  1.09  PARTICIPANT LOANS
  
        PARTICIPANT LOANS (check (a) or (b)):
  
        (a)  [ ] WILL BE ALLOWED IN ACCORDANCE WITH SECTION 7.09,
                 SUBJECT TO A $1,000 MINIMUM AMOUNT AND WILL BE
                 GRANTED (check (1) or (2)):
  
                 (1)  [ ] for any purpose.
                 (2)  [ ] for hardship withdrawal (as defined in
                          Section 7.10) purposes only.
  
        (b)  [X] WILL NOT BE ALLOWED.
  
  1.10  HARDSHIP WITHDRAWALS
  
        PARTICIPANT WITHDRAWALS FOR HARDSHIP PRIOR TO TERMINATION OF
        EMPLOYMENT (check one):
  
        (a)  [X]  WILL BE ALLOWED IN ACCORDANCE WITH SECTION 7.10,
                  SUBJECT TO A $1,000 MINIMUM AMOUNT.
  
        (b)  [ ]  WILL NOT BE ALLOWED.
  
                                                  (Replacement Page,
                                                   Third Amendment)
                                  13
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        ATTACHMENT TO ADOPTION AGREEMENT FOR GIANT INDUSTRIES, INC. 
                    AFFILIATED COMPANIES 401(K) PLAN
  
  Section 1.03(b).
  
       The Entry Date(s) shall include the first day of each month
       between June 25, 1998 and December 31, 1998, but only for an
       employee who was employed by Kaibab and was eligible to
       contribute to the Kaibab Industries, Inc. 401(k) Employee
       Savings Plan for Employees Not Covered under a Collective
       Bargaining Agreement ("the Kaibab 401(k) Plan") immediately
       before becoming an Employee of the Employer and who became an
       Employee of the Employer on or after May 21, 1998 and on or
       before December 31, 1998, in connection with the sale of
       certain assets of Kaibab to the Employer.
  
  Section 1.04(a)(4).
  
       Effective January 1, 1997, Compensation shall exclude (1) the
       value of a qualified or a nonqualified stock option granted to
       an Employee by the Employer to the extent such value is
       includable in the Employee's taxable income, (2) the amount
       realized from the exercise of a qualified or nonqualified stock
       option and (3) severance benefits.
  
  Section 1.05(c)(4)(A).
  
       An Employee of Giant Exploration & Production Company ("E&P")
       who is employed by E&P on July 16, 1996, and who is not
       thereafter transferred from E&P to another affiliate or
       division that is part of the Employer, shall be deemed to
       satisfy the requirements of this Section 1.05(c)(4)(A) for the
       Plan Year ending December 31, 1996.  
  
  Section 1.08
  
       (a)  Effective as of January 1, 1996, Bloomfield Refining
            Company ("Bloomfield"), The Gary-Williams Company ("Gary-
            Williams"), and any affiliate or predecessor employer of
            either, but only to the extent service was credited under
            The Gary Tax Advantaged Savings Program and Profit-Sharing
            Plan on October 4, 1995 with respect to such employer, and
            only for employees who were employed by Bloomfield or
            Gary-Williams on October 3, 1995, 
  
                                 -1-               (Replacement Page,
                                                    Third Amendment)
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            and became Employees of the Employer on October 4, 1995,
            in connection with the sale of assets of Bloomfield
            Refining Company to the Employer.
  
       (b)  Effective as of January 1, 1996, Meridian Oil Inc.,
            Meridian Oil Gathering Inc., and Meridian Oil Trading Inc.
            (collectively "Meridian"), and any affiliate or predecessor
            employer of Meridian, but only to the extent service was
            credited under the Burlington Resources Retirement Savings
            Plan on August 18, 1995 with respect to such employer, and
            only for employees who were employed by Meridian on August
            17, 1995, and became Employees of the Employer on August
            18, 1995, in connection with the sale of assets of Meridian
            to the Employer.
  
       (c)  Effective as of January 1, 1996, Texaco Refining and
            Marketing Inc. ("Texaco"), and any affiliate or predecessor
            employer of Texaco, but only to the extent service was
            credited under any plan sponsored by Texaco that qualified
            under Section 401(a)(4) of the Code, and only for an
            employee who was employed by Texaco on July 24, 1993, and
            became an Employee of the Employer on July 25, 1995 in
            connection with the sale of assets of Texaco to the
            Employer.
  
       (d)  Effective as of July 1, 1997, Thriftway Marketing
            Corporation ("Thriftway") for service before May 28, 1997
            but only for Pat Curtis, a human resource generalist, and
            for employees employed by Thriftway on May 27, 1997 who
            were employed or hired into the transportation division on
            or about May 28, 1997 and who became Employees of the
            Employer on May 28, 1997 in connection with the sale of
            assets of Thriftway and certain related entities to the
            Employer.
  
       (e)  Effective as of July 1, 1998, Kaibab Industries, Inc. 
            ("Kaibab") and any affiliate or predecessor employer of
            Kaibab, but only to the extent Service was granted under
            the Kaibab 401(k) Plan and only for an employee who was 
            employed by Kaibab immediately before becoming an Employee
            of the Employer and became an Employee of the Employer
            on or after May 21, 1998 and on or before December 31, 
            1998, in connection with the sale of certain assets to
            Kaibab to the Employer.
  
                                 -2-               (Replacement Page,
                                                    Third Amendment)
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  AMENDMENT TO BASIC PLAN DOCUMENT
  
    (a) By way of clarification and emphasis, Section 13.01 is amended
        by inserting the words "Discretionary authority" at the
        beginning of each of clauses (b)-(f), and in each such clause,
        revising "To" to read "to".
  
    (b) The second sentence of Section 4.10(a)(1) is amended by
        adding the following at the conclusion thereof: "; provided,
        that in the case of a direct rollover of an eligible rollover
        distribution from the Kaibab 401(k) Plan and the Kaibab
        Industries, Inc. Employee Stock Ownership Plan (the 'Kaibab
        plans'), the transfer may include a participant note for a plan
        Loan from one of the Kaibab plans."
  
    (c) By way of clarification and emphasis, Section 4.10(a)(2) is
        amended by inserting the phrase "any or all" between the words
        "accept" and "rollover" in both places they occur.
  
                                 -3-               (Replacement Page,
                                                    Third Amendment)